DESCRIPTION
This DTC is stored when the DCM (telematics transceiver) detects a malfunction in the telephone microphone assembly circuit.
DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
---|---|---|---|
B157213 | Microphone Circuit Open | Current at terminal MCVD is lower than the malfunction threshold for 10 seconds or more while the engine switch is on (IG) |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Safety Connect System.
Click here
PROCEDURE
1. | CHECK DTC |
(a) Turn the engine switch off.
(b) Connect the Techstream to the DLC3.
(c) Turn the engine switch on (IG) and wait for 10 seconds or more.
(d) Turn the Techstream on.
(e) Clear the DTCs.
Body Electrical > Telematics > Clear DTCs(f) Check for DTCs and check that no DTCs are output.
Body Electrical > Telematics > Trouble CodesOK:
No DTCs are output.
OK | ![]() | USE SIMULATION METHOD TO CHECK |
|
2. | CHECK HARNESS AND CONNECTOR (DCM [TELEMATICS TRANSCEIVER] - TELEPHONE MICROPHONE ASSEMBLY) |
(a) Disconnect the J157 DCM (telematics transceiver) connector.
(b) Disconnect the U15 telephone microphone assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
J157-5 (MCVD) - U15-1 (MACC) | Always | Below 1 Ω |
J157-6 (MCI+) - U15-2 (MIC+) | Always | Below 1 Ω |
J157-7 (MCI-) - U15-4 (MIC-) | Always | Below 1 Ω |
J157-23 (SGND) - Body ground | Always | 10 kΩ or higher |
J157-5 (MCVD) or U15-1 (MACC) - Body ground | Always | 10 kΩ or higher |
J157-6 (MCI+) or U15-2 (MIC+) - Body ground | Always | 10 kΩ or higher |
J157-7 (MCI-) or U15-4 (MIC-) - Body ground | Always | 10 kΩ or higher |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
3. | CHECK DCM (TELEMATICS TRANSCEIVER) (TELEPHONE MICROPHONE ASSEMBLY POWER SOURCE) |
(a) Remove the telephone microphone assembly but do not disconnect the connectors. Click here |
|
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Switch Condition | Specified Condition |
---|---|---|
U15-1 (MACC) - Body ground | Engine switch on (ACC) | 4 to 6 V |
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
U15-4 (MIC-) - Body ground | Always | Below 1 Ω |
OK | ![]() | REPLACE TELEPHONE MICROPHONE ASSEMBLY |
|
4. | REPLACE DCM (TELEMATICS TRANSCEIVER) |
(a) Replace the DCM (telematics transceiver) with a new one.
Click here
NOTICE:
NEXT | ![]() | PERFORM DCM ACTIVATION |
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Parking Assist Monitor System: Calibration
CALIBRATION ADJUST PARKING ASSIST MONITOR SYSTEM (a) The parking assist monitor system can be adjusted using diagnostic mode. (b) If the following operations are performed, it is necessary to perform adjustments and checks using diagnostic mode. Part Name Operation Adjustment Item Proceed t ...
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Wiper And Washer System: Fail-safe Chart
FAIL-SAFE CHART AUTO WIPER FAIL-SAFE FUNCTION (a) If the wiper system is malfunctioning, the windshield wiper motor and link assembly (wiper ECU) performs a fail-safe function to control the system. Item Fail-Safe Function Conditions to Return to Normal Condition Overheat protection Dec ...